A blurry future for Botox?

The cosmetic use of botulinum neurotoxins (BoNTs) to remove wrinkles might face an uncertain future. Produced by the bacterium Clostridium botulinum, BoNTs are among the most deadly natural toxins known; they interfere with the release of neurotransmitters—mainly acetylcholine—at the junction of nerves and muscles. These paralysing properties have been exploited to treat a range of serious pathological conditions such as cervical dystonia (severe neck muscle spasms), facial spasticity and strabismus (abnormal aligning of the eyes), and, more recently, to reduce facial wrinkles.
Until now, the use of BoNTs for cosmetic purposes—under the brand and popular name Botox—had been considered safe, in large part because it was assumed that the toxin remained confined to the injection site. However, an Italian research team at the National Research Council's Institute of Neuroscience in Pisa recently showed that this assumption might be wrong. To study the potential use of BoNT type A to block epilepsy, these researchers injected the toxin at various points in the face and brain of rats, including the whisker muscles and hippocampus. Days later, they found that the substance had unexpectedly spread from the whisker pad to the brain stem and crossed from one side of the brain to the other in the hippocampus, blocking hippocampal activity in the untreated hemisphere (Antonucci et al, 2008). This should raise some concerns about the safety of BoNT injections as it revealed the ability of the toxin to travel along nerve cells while remaining active.
Earlier this year, the US Food and Drug Administration (FDA) had already warned that it had "received reports of systemic adverse reactions including respiratory compromise and death following the use of botulinum toxins [...] The reactions reported are suggestive of botulism, which occurs when botulinum toxin spreads in the body beyond the site where it was injected" (FDA, 2008). The question is whether this is enough evidence to ban the cosmetic use of BoNTs. "I don't think that fear is warranted. Thousands of people have already taken the drug for cosmetic purposes, with few reports of side effects", said Matteo Caleo, the study's lead author. "At the same time, I believe that the issue of BoNT/A trafficking should be further investigated. It is important to characterize completely the spectrum of actions of a drug that is so widely used."


Forwarded by Dr. Subroto Chatterjee